Method and device for wrapping groups of stacked products in the manufacture of sealed packs

ABSTRACT

Groups of products stacked on edge are wrapped in sealed stick packs by a method that involves passing a sheet ( 4 ) of heat-sealable wrapping material around each group ( 1 ) of products ( 2 ) and sealing the two side edges ( 8 ) in such a way as to fashion a tubular wrapper ( 12 ) with end portions ( 14 ) projecting axially from the assembled group ( 1 ), then spreading each end portion ( 14 ) flat by inserting a tongue ( 16 ) and heat-sealing each relative pair of flattened edges to render the wrapper airtight. Thereafter, the sealed ends are subjected to a cold crimping action from which each end portion ( 14 ) emerges with two impressed crease lines ( 24 ) positioned to delimit a central portion ( 25 ) that will be folded directly against the corresponding end face of the group ( 1 ), and two lateral portions ( 26 ) that will be folded inwards over the central portion ( 25 ).

This application is the National Phase of International ApplicationPCT/IB2004/000576 filed Feb. 23, 2004 which designated the U.S. and thatInternational Application was published under PCT Article 21(2) inEnglish.

This application claims priority to Italian Patent application numberBO2003A 000093, filed Feb. 25, 2005, which is incorporated by referenceherein.

TECHNICAL FIELD

The present invention relates to a method and a device for wrappinggroups of stacked products in the manufacture of sealed packs.

In particular, the present invention relates to a method and a devicefinding useful application in the confectionery or pharmaceuticalindustry for making stick packs of sweets or pastilles.

BACKGROUND ART

As a rule, products wrapped in stick packs for general retail are oftypically flat parallelepiped shape and ordered into a wrappable groupone beside the next, with the larger faces disposed transversely to thepredominating axis of the assembled group. Accordingly, the group ofproducts will present at least one relatively small transversedimension, and the stick pack is fashioned using simple heat seal jawsby which the projecting edges of a tubular wrapper formed around thegroup can be gripped and secured tight against the ends of the groupwithout generating random creases or other imperfections that might intime allow air into the finished pack.

The above considerations do not apply to another type of stick pack ongeneral sale, in which the products are again ordered one beside thenext with the larger faces in mutual contact, though in this instanceforming a much more compact group generally of square or rectangularsection. The ends of this type of stick are ordinarily not sealed, butsimply folded. In the event of a sealed end being required for thissecond type of stick pack, the seal is obtained starting from a tubularwrapper of which the trimmable ends project an appreciable distancebeyond the end faces of the group of products. By virtue of this extralength, the opposite edges presented by each end of the wrapper can bepinched together. Sticks presenting this type of seal are however notreadily acceptable in terms of appearance, difficult to stack, unable toretain the wrapped products in close contact one with another, andinclined to break or tear open easily at the ends.

The prior art also embraces a method for forming packets of the typedescribed above, disclosed in patent DE 3420023 by the same applicant,which envisages the step of fashioning a tubular wrapper initiallyaround the group of stacked products and then closing the ends of thewrapper. The process of closing each end includes a first step in whichthe ends are drawn flat, by inserting flat spreader means, and united bythe action of sealing and crimping means designed to impress creaselines on each of the flattened ends so as to facilitate a subsequentfolding step. In practice, the final step occurs with the sealed andcrimped end already presenting a central portion, and two lateralportions delimited on either side of the central portion by the creaselines. The central portion is folded against the end face of the groupof products and the lateral portions are then folded over the centralportion.

The method described above likewise presents certain drawbacks connectedprincipally with the step in which the sealing and crimping operationsoccur. In effect, a dependable closure of the ends cannot be assuredwhen the sealing and crimping steps are combined, since the sealing jawsare not able to unite the edges of the wrapper faultlessly along thecrease lines.

The object of the present invention is to set forth a method and adevice free of the drawbacks mentioned above, by means of which productsstacked on edge and in contact one with the next by way of their largerfaces can be packaged in a sealed wrapping.

DISCLOSURE OF THE INVENTION

The stated object is realized by adopting a method and a device forwrapping groups of stacked products in the manufacture of sealed packs,as recited in one or more of the claims appended.

The invention will now be described in detail, by way of example, withthe aid of the accompanying drawings, in which:

FIG. 1 illustrates a wrapping line of a sweet packaging machine embodiedaccording to the present invention, viewed schematically and inperspective;

FIG. 2 illustrates a first detail of the device according to the presentinvention, shown in a first operating step;

FIGS. 3 and 4 show a second detail of the device disclosed, illustratedin respective subsidiary steps of a second operating step;

FIG. 5 illustrates a third detail of the device disclosed in a thirdoperating step;

FIGS. 6 and 7 show a fourth detail of the device disclosed, illustratedin respective subsidiary steps of a fourth operating step;

FIG. 8 is an elevation view showing the detail of FIG. 7;

FIG. 9 shows the subsidiary step of FIG. 6 from a different standpointand with certain parts omitted better to reveal others;

FIG. 10 shows a portion of the fourth detail as in FIGS. 6 and 7, frombeneath and in perspective;

FIGS. 11 and 12 are perspective views illustrating a fifth detail of thedevice disclosed in respective subsidiary steps of a fifth operatingstep.

FIG. 1 of the drawings illustrates a wrapping line of a machine (notillustrated) for packaging groups 1 of products 2, in particular itemsof confectionery such as sweets presenting a flat parallelepiped shape,stacked on edge with the larger flat faces offered one to the next.

At the start of the wrapping line, the assembled group 1 is directedinto a first wrapping station 3 where a sheet 4 of heat-sealablewrapping material is positioned over the selfsame group 1 by feed meansnot illustrated in the drawings.

From this position, the group 1 is directed by the action of pushermeans (not illustrated) against the wrapping sheet 4 and through afolding shoe 5, with the result that the sheet 4 will be bent over thelateral faces of the group 1 to assume a “U” profile. As indicated inFIG. 2, the group 1 is inserted together with the sheet 4 into aconveying pocket 6 afforded by the periphery of a wrapping wheel 7,extending parallel to a straight line generator of the wheel 7. Ineffect, the wheel 7 is furnished with a plurality of such pockets 6 eachserving to accommodate one group 1 enveloped by a respective sheet 4.The wheel is also rotatable in such a way as to direct each group 1 ofproducts 2 through a series of wrapping stations.

As discernible in FIG. 2, the wrapping sheet 4 is disposed with twoopposite side edges 8 projecting radially from the relative pocket 6,and these same edges are directed into contact one with another by aheat-sealer 9 of which one jaw consists in a heat seal element 10 andthe other a reaction element 11. The heat-sealer 9 serves to form atubular wrapper 12 presenting a heat-sealed fin 13 along one side,formed by joining the two edges 8, and two tubular extremities or endportions 14 projecting beyond the opposite ends both of the group 1 ofproducts and of the relative pocket 6.

The group 1 and the relative tubular wrapper 12 are directed by thewheel 7 as it indexes through a step of predetermined angular distance,for example 90°, to a second wrapping station 15 where a tongue 16 isintroduced into each of the two end portions 14, as indicated in FIGS. 3and 4. The tongue is tapered toward the free end and insertable thusgradually into the relative end portion 14 in such a manner as to spreadand flatten the tubular extremity progressively, causing it to assume aposition substantially tangential to the periphery of the wheel 7 andstretching the material slightly so as to induce a measure of plasticdeformation that will render the flattened configuration permanent.

Thereafter, and still at the second station 15, the tongues 16 arewithdrawn and the end portions 14 pinched and fastened together, asillustrated in FIG. 5, by the action of respective heat-sealers 17operating on the selfsame portions 14.

Each of the heat-sealers 17 in question comprises two heat seal elements18 and 19 presenting relative flat heated surfaces 18 a and 19 a capableof movement toward and away from one another. Following the action ofthe heat-sealers 17, each end portion 14 remains permanently sealed,presenting a flat seam.

With reference to FIGS. 6 . . . 12, the group 1 and the relative wrapper12 are directed by the wrapping wheel 7, indexing through a furtherangle preferably of 90°, to a third wrapping station 20 that consists ina folding unit 21 by which each of the flattened end portions 14 iscrimped and folded against the respective end face of the group 1.

The folding unit 21 comprises a first folder element 22 and a secondfolder element 23 presenting respective contact ends 22 a and 23 acapable of movement between a position distanced one from the other, anda position of mutual proximity in which the relative flattened endportion 14 of the wrapper is gripped between them and crimped togenerate crease lines 24 dividing the end portion 14 into a centralportion 25 and two lateral portions 26. The two crease lines 24 are thusformed by a cold crimping step following the heat-seal closure of theends and, in the preferred embodiment of the drawings, will extendsubstantially parallel to the longitudinal axis of the tubular wrapper12.

More exactly, the contact end 22 a of the first folder element 22 is ofparallelepiped geometry and presents a dimension T1, measuredtransversely to the axis of the tubular wrapper 12, smaller than thecorresponding transverse dimension T2 of the sealed end portion 14 (FIG.9). To advantage, moreover, the contact end 23 a of the second folderelement 23 presents a U profile creating a recess 27 designed toaccommodate the contact end 22 a of the first folder element 22. Thedimension of each folder element 22 and 23 measured parallel to thelongitudinal axis of the wrapper 12, denoted D1 and D2 respectively, isat least equal to the corresponding axial dimension D3 of the endportion 14.

More exactly, as illustrated in FIG. 7, the two crease lines 24 areimpressed on the flattened end portion 14 by bending the two lateralportions 26 in relation to the central portion 25 along fold linescoinciding with the crease lines 24. The fold lines are established bythe two internal corners 27 a of the U-profiled recess 27.

The first folder element 22 and the second folder element 23 areafforded by respective arms 28 and 29 of which respective first ends 28a and 29 a present the contact ends 22 a and 23 a, and respective secondends, not illustrated, are mounted pivotably so that the arms can rotatebetween the distanced position and the position of mutual proximity.

After the one arm 29 has been distanced from the other arm 28, the firstfolder element 22 rotates beyond the position occupied when in proximityto the second folder element 23, in such a way as to fold the centralportion 25 against the corresponding end face of the group 1 (see FIG.11).

As a result of crimping the end portion 14 to produce the crease lines24, the step of folding the central portion 25 against the relative endface of the group 1 will cause the two lateral portions 26 to projectaxially from the group 1 and externally of the respective pocket 6.

At this juncture, as discernible in FIG. 12, the lateral portion 26positioned upstream relative to the direction of movement of thewrapping wheel 7 is folded over the central portion 25 by a third folderelement 30 capable of movement in a direction perpendicular to the axisof the wheel 7, whereupon the remaining lateral portion 26 will befolded over the central portion 25 through the agency of a fixed folderelement 31 by which it is intercepted as the wheel 7 continues torotate.

The fixed folder element 31 is positioned to engage the second lateralportion 26 as the wrapping wheel 7 indexes through a furtherpredetermined angle, again preferably 90°, to bring each stick pack 32,consisting in a group 1 of products 2 enveloped by a fully folded andsealed wrapper 12, into an outfeed station 33 where the packs 32 areejected radially from the respective pockets 6 through the action ofradial pusher means not illustrated in the drawings.

The invention affords important advantages.

First and foremost, the method according to the invention isinstrumental in producing singularly compact and rigid packets by whichthe stacked products are firmly retained.

Moreover, the packets emerge faultlessly sealed at the two ends, so thatneither air nor impurities can infiltrate.

1. A method for wrapping groups of stacked products in the manufactureof sealed packs, comprising the steps of: folding a sheet ofheat-sealable wrapping material around a group of products; sealingtogether two side edges of each sheet so as to fashion the sheet into atubular wrapper having end faces, with end portions projecting axiallyfrom the group; introducing a tongue into each tubular end portion insuch a way as to spread and deform the end portion, causing it to assumea flattened appearance; closing each flattened end portion by means of aheat-sealer to form closed end portions; generating two crease lines oneach closed end portion to divide each closed end portion into a centralportion and two lateral portions, wherein the step of generating twocrease lines on each closed end portion includes crimping each closedend portion between a first folder element and a second folder elementpresenting respective contact ends capable of movement between aposition distanced one from the other and a position of proximity of oneto another; constructing and arranging the contact end of the firstfolder element to be of parallelepiped geometry and having a transversedimension smaller than a transverse dimension of the closed end portion;constructing and arranging the contact end of the second folder elementto present a “U-shaped” profile having a recess to accommodate thecontact end of the first folder element; folding the central portionagainst the respective end face of the group; folding each of the twolateral portions over the central portion.
 2. A method as in claim 1,wherein the step of generating two crease lines on the flattened endportion involves bending the two lateral portions relative to thecentral portion along lines coinciding with the crease lines.
 3. Adevice for wrapping groups of stacked products in the manufacture ofsealed packs, comprising: feed means for positioning a sheet of wrappingmaterial over a group of products; pusher means for directing the groupof products against the sheet and through a folding shoe such that thesheet is bent around the group to assume a “U-shaped” profile; awrapping wheel equipped with a plurality of conveying pockets toaccommodate a group of products enveloped by the sheet with two sideedges of the sheet projecting radially from the pocket, the wrappingwheel rotatable to direct each successive group of products throughrespective wrapping stations comprising a heat-sealer sealing twoopposite side edges of the sheet, creating a tubular wrapper with endfaces, with two end portions projecting externally of the pocket, atongue by which the end portion is deformed and caused to assume aflattened appearance, heat-sealing means capable of movement toward andaway from one another and sealing the flattened end portions, and afolding unit to fold the sealed end portions against the respective endfaces of the group of products; the folding unit comprising a firstfolder element and a second folder element presenting respective contactends capable of movement between a position distanced one from the otherand a position of mutual proximity in which the respective sealed endportion of the wrapper is crimped between the contact ends to generatecrease lines dividing the end portion into a central portion and twolateral portions, the contact end of the first folder element being ofparallelepiped geometry and having a transverse dimension smaller than atransverse dimension of the sealed end portion, the contact end of thesecond folder element having a “U-shaped” profile having a recess toaccommodate the contact end of the first folder element.
 4. A device asin claim 3, wherein the first folder element and the second folderelement further comprise respective arms presenting respective firstends and being pivotable between a position distanced one from anotherand a position of proximity one to another.
 5. A device as in claim 3,wherein the heat-sealing means comprise two heat seal elementspresenting respective flat heated surfaces.
 6. A device as in claim 3,wherein the first folder element folds the central portion of the endportion against the corresponding end face of the group.
 7. A device asin claim 6, wherein the folding unit further comprises a third folderelement capable of movement in a plane perpendicular to the axis of thewheel and serving to fold one of the lateral portions against thecentral portion.
 8. A device as in claim 7, wherein the folding unitfurther comprises a fixed folder element by which the remaining lateralportion is engaged during the rotation of the wheel and folded againstthe central portion.